1. Field of the Invention
The present invention relates to an apparatus and method of predicting a radio wave environment, and more particularly, to an apparatus and method of predicting a radio wave environment using a ray tracing scheme.
2. Description of the Related Art
As a method of predicting and modeling a radio wave environment, a statistical approach method and a theoretical approach method which are based on extensive measurement results may be used. A ray tracing scheme as an example of the theoretical approach method may predict a radio wave environment with relatively accuracy in comparison with other radio-wave prediction methods.
In a radio wave environment of a city, there exist many factors that may need to be considered, such as arrangement, height, materials, and directions of buildings, and the like and thus, as a method for predicting a radio wave environment, a ray launching scheme may be widely used. The ray launching scheme is performed such that an intensity of a received radio wave may be calculated based on a reflection process, a diffraction process, and the like which a radio wave is subjected to, until a ray emitted in a predetermined angle, spaced apart from a transmission point, arrives at a reception point.
A reception method of the ray launching scheme among conventional ray tracing methods may be performed using a reception radius (for example, a reception sphere which is three dimensional (3D), and a reception circle which is two dimensional (2D)). In the reception method of the ray launching scheme, infinite rays emitted from the transmission point may be replaced with finite rays, and a path running until each of the finite rays is sequentially emitted, and then arrives the reception point may be traced. Accordingly, in the reception method of the ray launching scheme, a path loss or a delay distribution may be calculated by summing powers of rays received in the reception point based on the traced to multiple paths. In this instance, when a transmitted signal enters within the reception radius, the signal may be considered as arriving at the reception point.
In an initial concept for the reception radius, the reception radius may be calculated as the same value as ‘1’ based on an assumption that an overall area of the reception radius is 1, however, the calculation of the reception radius does not refer to the reception radius varying based on a distance change between the transmission point and the reception point thus, may cause an occurrence of double counting and a dead zone.
Accordingly, in a radio-wave environment prediction performed using the ray tracing scheme, there is a demand for a method that may improve the reception radius by referring to the distance change between the transmission point and the reception point while preventing the double counting and the dead zone from occurring, and also requiring a relatively fewer calculations.